Sr n +1 Ti n O 3 n +1 (n=1, 2) microwave dielectric ceramics with medium dielectric constant and ultra‐low dielectric loss

Sr n +1 Ti n O 3 n +1 (n=1, 2) ceramics with tetragonal Ruddlesden–Popper structure were prepared via a standard solid‐state reaction process, and their microstructures and microwave dielectric properties were investigated systematically. The phase composition, grain morphology, and densification behavior were explored using X‐ray diffraction ( XRD ) and scanning electron microscopy ( SEM ). Outstanding microwave dielectric properties were achieved in the present ceramics: ε r =42, Q  ×  f =145 200  GH z, τ f =130 ppm/°C for Sr 2 TiO 4 , and ε r =63, Q  ×  f =84 000  GH z, τ f =293 ppm/°C for Sr 3 Ti 2 O 7 , respectively. The present ceramics might be expected as excellent candidates for next‐generation medium‐permittivity microwave dielectric ceramics after the further optimization of τ f value.